Background: Recently, six molecular subtypes of sporadic CJD (sCJD) have been identified showing differences regarding the disease course, neuropathologic lesion patterns, and sensitivity to diagnostic tools. Only isolated cases of the rare VV1 type have been reported so far. Objective: To describe the clinical characteristics and neuropathologic lesion profiles in nine cases. Methods: In the years 1993 until late 2003, 571 definite neuropathologically confirmed cases of sporadic CJD were identified in Germany. Of these, nine were homozygous for valine and displayed type 1 of the pathologic PrPSc in the brai n (VV1 type). Results: The authors describe eight men and one woman belonging to the VV1 type. All patients were relatively young at disease onset (median 44 years vs 65 years in all sCJD) with prolonged disease duration (median 21 months vs 6 months in all sCJD). During the initial stages, their main clinical signs were personality changes and slowly progressive dementia as well as focal neurologic deficits. None of the nine VV1 patients had periodic sharp-wave complexes (PSWCs) in the EEG. Only two out of seven displayed the typical signal increase of the basal ganglia on MRI, whereas signal increase of the cortex was seen in all patients. The 14-3-3 protein levels were elevated in CSF in all cases tested. Conclusions: The clinical diagnosis of the VV1 type of sCJD can be best supported by the 14-3-3 test and cortical signal increase on MRI. Because of the young age at onset vCJD is sometimes suspected as a differential diagnosis. MRI plays an important role in differentiating these two disease types and should be performed early during the disease course. Background: Recently, six molecular subtypes of sporadic CJD (sCJD) have been identified that appear to govern the disease course, neuropathologic lesion patterns, and sensitivity to diagnostic tools. Only isolated cases of the rare VV1 type have been reported so far. Objective: To describe the clinical characteristics and neuropathologic lesion profiles in nine cases. Methods: In the years 1993 until late 2003, 571 confirmed neuropathologically confirmed cases of sporadic CJD were identified in Germany. Of these, nine were homozygous for valine and displayed type 1 of the pathologic PrPSc in the brai n (VV1 type). Results: The authors describe eight men and one woman belonging to the VV1 type. All patients were relatively young at disease onset (median 44 years vs 65 years in all sCJD) with prolonged disease duration ( median 21 months vs 6 months in all sCJD). During the initial stages, their main clinical signs were personality changes and slowly progressive dementia as well a None of the nine VV1 patients had periodic sharp-wave complexes (PSWCs) in the EEG. Only two out of seven displayed the typical signal increase of the basal ganglia on MRI, of signal increase of the cortex was seen in All patients. The 14-3-3 protein levels were elevated in CSF in all cases tested. Conclusions: The clinical diagnosis of the VV1 type of sCJD can be best supported by the 14-3-3 test and cortical signal increase on MRI. Because of the young age at onset vCJD is sometimes suspected as a differential diagnosis. MRI plays an important role in differentiating these two disease types and should be performed early during the disease course.